Aerofoil of Buran

The structure of Buran wich made it flight is called the aerofoil, it is composed of aerodynamic shaped, which supports the constraints during the flight, and includes the systems and the elements ensuring the descent and the landing. Its mass, including with its systems, makes nearly 40% of the starting mass of Buran.
The structure of the aerofoil (without the heat shield) ensures the arrangement and the protection of the crew, the payload and the various systems during all the stages of the flight. The aerofoil includes:

• the hermetic module of the cabin for the crew;
• the nasal part of the fuselage, panes and the entry trap door;
• the payload bay whose leaves open, plus the ventilation leaves, transmission nodes with Energia;
• the part of tail of the fuselage, with hang fixings of the vertical stabilizer, the transmission nodes with Energia, the propulsion system and the leaves of ventilation;
• the balancer shield;
• consoles of control of the wing with the aerodynamic bodies (ailerons), the leading edge, and the residences for the landing gears
• the vertical stabilizer made up of the drift which has also the function of air-brake;
• fasteners of the apparatuses, the equipment, piping, cables, etc.

Caption:
1- nasal shield; 2-nasal part of the fuselage, machines; 3-block of gas engines; 4-hermetic cabin; 5-wing; 6-leading edge of carbon; 7-elevons; 8-protection of the elevons; 9-central part of the fuselage; 10-drift; 11-rudder; 12-tail of the fuselage; 13-balancer shield; 14-doors of the payload bay with heat exchanger; 15-trap door of the landing gear; 16-landing gear; 17-trap door of the front landing gear; 18-front landing gear; 19-entry trap door

The design of the aerofoil takes into account the forces which are exerted at the frame, the aerodynamics forces, the vibratory forces, the concentrated forces and the moments generated by the payload, the constraints at the hang anchoring with Energia, the thrust of the engines and the constraints of the landing gears. The following elements are used to rigidify the structure of the aerofoil:

• reinforced longitudinal panels on all the external surface;
• stringer curved beams to absorb the loads;
• weight-bearing frames;
• beams and strengthening pieces of the wing and the vertical stabilizer;

The presence in the central part of the fuselage and at the beginning of the wings of the ventilation system asked for the introduction of additional elements to rigidify the structure.

Shuttle assembly:

 

The shuttle in assembling whose necessary systems to the space flight and equipment represented nearly 20% of the starting mass of the shuttle. The universal equipment for work with the payload and the interchangeable sections made up to 11% of the mass. On the left the assembly of the aerofoil in the factory.

At the time of creation of Buran, it was decided to create a "cold" heat shield for the interiors parts of the sailplane (-130 with +160°C), moreover the nose and the leading edge of the wings are covered with a resistant matter to heat containing carbon and of thermal barriers for the connection zones with the main structure had to be elaborate.

In addition, technical choices have been made on the intense sound level related to the rigidity the structure and with the heat shield so that the equipments and the safety of the crew are guaranteed.

The extreme constraints on the structure are observed at the beginning and the transonic flight. At the beginning and during the initial phase of the flight the vibrations are generated by the engines of Energia, but it is at the time of the descent, which is accompanied transonic speeds, that the levels are maxima.

The elevons of the wing are composed of 2 parts (interior and external), they are fixed by 3 points of fastener at the back of the wing. Each section is controlled in an autonomous way by a mechanism located in the wing, ensuring an angle of beat of 35° to the top and of 20° downward.

So that the structure and the elements of the shuttle have the lowest possible mass, simulations in the TsAGI institut were conducted. These numerical studies made it possible to define the constrained and deformed states of the structure:

• deformation of the fuselage and the doors of the payload bay under various constraints;
• evolution of the structure under concentrated loadings;
• calculation of the various dilation coefficients and deformations caused by not uniform temperatures of materials, etc.

Except for static calculations, calculations were refined for:

• solidity under dynamic constraints during the departure, the flight, the separation of Buran and Energia, the trajectory in orbit, the entry in the dense layers of the atmosphere and the landing;
• the stability of the elements of the structure subjected to the phenomena of aeroelasticity in particular at the time exiting the orbit and during the descent;
• impact of the acoustic vibrations during the departure, the putting in orbit and the descent;
• additional constraints due to non-uniformity of the temperatur field, being able to reach until 50°C on particular elements.